THE CHAMP 300 AMPLIFIER (8 x 6L6 Output Tubes)


Hello Guy's 'n' Dolls. I realise it's about two months since I last added an article to the site (on 20/08/09)…….I have been overwhelmingly busy! Not to worry though, as there are plenty more goodies coming soon, and this will include some new amplifier manufacturers' brand names too. As a quick interim update though, I thought you might find this one interesting?

I have recently purchased a great little gadget that transfers 35mm negatives straight to the computer hard-drive via USB… really is a great little thing. Slowly, in-between everything else that I have to deal with, I have been going through my (roughly) 3000 negatives from almost the past 55 years! Most of them I can remember, and also pretty much have them in my photo albums collection anyway. But….some have come through that I had forgotten about and don't have in the albums…….hence this article. These are photos taken of my first-ever 300 watt amp using 8 x 6L6's for the output……..c1971. The photos are not perfect but can still be seen OK, and my caption texts tell it all.

Thanks for all your continued support, constant kind words, and interest in the site.

Cheers, John. 

I was really pleased to have found these photos. Front shot of the amp here. The tube line-up is: 2 x ECC83, 2 x ECC81 and 8 x 6L6. I remember it sounded really good and punchy! In the background you can see my originally home-made mono dummy load…..which later got re-made into a much more practical stereo version. - Please see here:

Also in the background, on top of the dummy load and to the left is my original old Eagle Products valve signal generator, and at the right-hand side of this was a big stack of GEC KT88's!

Showing one end of the underside.

Showing the opposite end, underside. Here you can see the miniature RS choke (at the bottom), which I used for the DC bias supply, and series connected pre-amp heaters. You can also see the bias protection relay.

The full underside. Sorry about the crap camera work….I've learnt a lot more about photography since taking these photos way back in 1971! Still, I think my wiring was pretty tidy even as far back as this and….8 x separate individual bias pots too! Who was doing that back in 1971?

Simple top view. Oh, and yes…..I did make the two 3" stack transformers myself.

And of course the rear view. I remember at the time that I didn't have a full set of the same make of 6L6's, so I ended up putting the ones in that I had, and trying to make each half look correct. To do this I ended up with (working from the middle out…both ways) a pair of Sylvania's, a pair of "black-plate" RCA, a pair of Russian GC's & finally an odd pair of 6L6G's. I think one was a Brimar but I can't remember what the other was. Still, with having the individual bias pots and the rear mounted 8-way switch and meter, it didn't really matter about "mix & match" output tubes as they can all be controlled equally! All great fun back in the old days.

This last photo was on the same set of negatives and I have included it, despite it being rather blurred, because it is the only photo of this amp that I have. It is exactly the same design as the amp in the photos above butit is actually a 400 watt version using 8 x EL34's with 800 volts on the plates. Also note the top-mounted plate with two cooling fans blowing down at the tubes! Who was fitting cooling fans to tube amps back in 1971?…..Maybe Ampeg's SVT was the first? 

Cheers, John.